A skilled mechanic's time is very valuable, and for this reason, it is quite important to reduce to a minimum that portion of his working time that is typically involved in work elements that are largely routine or highly repetitive in nature.
One operation that a mechanic performs many times during the course of the day, and an operation that does not utilize his special knowledge or skills, is the repeated adjustment and readjustment of a crescent wrench to fit nuts and bolts of various dimensions. This is especially true where the successive nuts or bolts encountered vary in dimension from very large to very small. A brief experience in this kind of work environment makes it quite apparent that an appreciable part of the working time is devoted to the adjustment and readjustment of the wrench.